Suchergebnisse

Measles and rubella are important causes of morbidity and mortality globally. Despite high coverage reported for measles vaccination, outbreaks continue to occur in some countries. The reasons for these outbreaks are poorly understood. We apply Bayesian methods to multi-valent seroprevalence data for measles and rubella, collected 2 years and 3 months after a mass measles-rubella vaccination campaign in Lao PDR to estimate the immunogenicity and vaccination coverage. When the vaccination coverage was constrained to exceed 95% or 90%, consistent with officially-reported values, the immunogenicity of the measles vaccine component was unexpectedly low (75% (95% CR: 63-82%) and 79% (CR: 70-87%) respectively. The estimated immunogenicity increased after relaxing constraints on the vaccination coverage, with best-fitting values of 83% (95% CR: 73-91%) and 97% (95% CR: 90-100%) for the measles and rubella components respectively, with an estimated coverage of 83% (95% CR: 80-88%). The findings suggest that, if the vaccine coverage was as high as that reported, continuing measles outbreaks in Lao PDR, and potentially elsewhere, may be attributable to suboptimal immunogenicity attained in mass campaigns. Vaccine management in countries with high reported levels of coverage and ongoing measles outbreaks needs to be reviewed if measles elimination targets are to be achieved.

The Ministry of Health and Family Planning of Madagascar introduced Integrated Management of Childhood Illness (IMCI) strategy in 2006, and community-based IMCI (c-IMCI), in Mahajanga II District in 2007. Following the 2009 political crisis, foreign organisations' suspension of development aid until 2012 significantly affected the implementation of c-IMCI. This study aimed to elucidate the perspectives of village health volunteers (VHVs) and public health officers (PHO) on c-IMCI. Semi-structured in-depth interviews with all VHVs working in three communes and PHOs working at central, district, and health centre levels were conducted in 2013. Textual data, created from transcripts, were translated into English and French. Data management involved analysis of sections of translated transcripts, which were marked, coded, and linked with similar experiences, challenges, and opinions; these were categorised into words and phrases to discover meaningful relationships between emerging themes. From all interviews of 30 VHV in three Mahajanga II communes and 4 PHOs, 3 themes emerged: 1) benefits of c-IMCI to the community and for VHVs, 2) challenges to continue c-IMCI, and 3) motivation to continue c-IMCI. Although all respondents considered c-IMCI as beneficial, they stated it was difficult to continue. The health system and implementation of c-IMCI should be strengthened to enable programme survival beyond the initial phase, especially during times of political instability.

BACKGROUND: Measles outbreaks have occurred in some countries despite supplementary immunization activities (SIA) using measles-containing vaccine with high vaccination coverage. We conducted a cross-sectional seroprevalence survey to estimate population immunity in Lao People's Democratic Republic where repeated mass immunization has failed to eliminate measles. METHODS AND FINDINGS: In this nationwide multistage cluster sampling survey conducted in 2014 based on probability proportionate to size sampling, blood samples were collected from 2,135 children and adults living in 52 randomly selected villages. Anti-measles and anti-rubella IgG were measured, and IgG prevalence was calculated. We applied mathematical modelling to estimate the number of cases of congenital rubella syndrome (CRS) in 2013 that were averted by the 2011 SIA. A stability testing was applied to the MR vaccine at 4°C, 25°C, and 35°C to examine stability differences between measles and rubella vaccine components. Measles IgG prevalence was significantly lower in the target age groups (5-21 years) of the 2011 SIA using a combination vaccine for measles and rubella vaccine (MR vaccine) than in young adults (22-39 years) (86.8% [95% CI: 83.0-90.6] vs. 99.0% [98.3-99.8]; p<0.001), whereas rubella IgG prevalence was significantly higher (88.2% [84.5-91.8] vs. 74.6% [70.7-78.5]; p<0.001). In the SIA target age groups, prevalence of measles IgG, but not rubella IgG, increased with age. CRS cases prevented in 2013 ranged from 16 [0-50] to 92 [32-180] if the force of infection had remained unchanged or had been reduced by 75%, respectively. In freeze-dried conditions, the measles vaccine component was more heat sensitive than the rubella component. CONCLUSIONS: Inconsistent IgG prevalence between measles and rubella in Lao PDR can be partly explained by different stability of the measles and rubella vaccine components under heat exposure. Suboptimal vaccine handling may cause insufficient immunogenicity for measles, which subsequently leads to an outbreak despite high SIA coverage, while direct evidence is lacking. Temperature monitoring of the vaccine should be conducted.